The hydraulic gradient is a measure of the slope of the
potentiometric surface. Groundwater flows from a higher
hydraulic head to a lower hydraulic head.

The potentiometric surface of the Muddy Sandstone
slopes to the east-southeast in the Denver-Julesburg basin,
as shown on Plate I. The general direction of groundwater
flow is, therefore, to the east-southeast from the Laramie
Range. If recharge does flow past the fault severed
boundary along the flank of the range, then the potential
does exist for that recharge to flow towards the basin
interior.

The possibility that significant recharge flows past
the fault severed boundary is remote because the fault plane
is impermeable. Effects of the impermeable fault plane
documented in the study area include stream flow gains along
the upper segment of the gauged reach of the North Fork of
Horse Creek and the line of springs along the eastern most
thrust fault on Plate IV, located east of Table Mountain.